Now whenever I see a map of the Underground I have a partial mapping of the stations onto memories, which is a nicely weird experience. If I were to go on another vacation to Washington DC and take the subway there I could observe the formation of this mapping in near-real time. As it is, I have only a couple vague memories from my trip when I was 6: being between stations underneath the Potomac, imagining humidity and dripping water; being told by my father that Foggy Bottom was called that because it was actually underwater, at the bottom of the Potomac; standing on the Triangle platform watching a train arrive.

Of course, I have memories of various kinds associated with over half of the BART stops. There must be a point at which you've used a subway system so much that the stops stop being useful as mnemonic devices for remembering things you did.

Bonus game: without looking at the source code, can you find the link to Crummy on kottke.org?